This invention relates to a motorcycle, and more particularly to a fuel tank and a fuel feed system thereof.
In a motorcycle, a fuel tank is usually disposed on a main pipe at an upper location of an engine, therefore the tank is disposed higher than a carburetor. Accordingly, fuel is fed from the fuel tank to a float chamber of the carburetor by a natural downward flow due to its own weight. In such a motorcycle as just mentioned, when capacity of the fuel tank is to be greatly increased either the tanks width is made wider or the tanks height is made larger. The reason is that the length is limited within a certain range.
However, if the width of the fuel tank is widened, a rider will find it difficult to ride on the motorcycle. Moreover, since a full fuel tanks weight is increased in ratio with respect to the vehicle body weight, the center of gravity of the whole vehicle is. Furthermore, since the liquid surface within the fuel tank increases, the liquid surface is fluctuated largely due to the jolting of the vehicle body which causes the fuel feed quantity to the carburetor to change.
When the height of the fuel tank is increases, a bottom portion of the tank will be lower than the position where the carburetor is located. Accordingly, an additional fuel pump must be installed in order to effectively consume the fuel within the fuel tank. However, addition of such a fuel tank invites an increase in weight of the vehicle body as well as an increase in cost.